Intervertebral fusion implant

ABSTRACT

The present invention includes a pedicle screw made with a bone fastener and a rod coupling head, the rod coupling head comprising an upper rod coupling: the lower rod coupling having a lateral rod opening adapted to receive a permanent rod; an angled bore extends into the lateral rod opening; and a permanent rod fastener in the angled bore to engage a permanent rod in the lateral rod opening; and a upper rod coupling having an upper rod opening adapted to receive a temporary rod, wherein the upper rod opening is formed to receive a temporary rod fastener; wherein the upper rod coupling is detachable from the lower rod coupling at a transition and a temporary rod is temporarily affixed into the upper rod opening during a bone realignment and a permanent rod is positioned in the lateral rod opening and engaged by the permanent rod fastener upon final bone alignment.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation of U.S. patent applicationSer. No. 15/352,622, filed Nov. 16, 2016, which is a continuation ofU.S. patent application Ser. No. 14/699,937, filed Apr. 29, 2015, nowU.S. Pat. No. 9,526,526, which is a divisional patent application ofU.S. patent application Ser. No. 12/364,423, filed Feb. 2, 2009, nowU.S. Pat. No. 9,050,141, which is a non-provisional patent applicationof and claims priority to U.S. Provisional Application Ser. No.61/025,760 filed Feb. 2, 2008 and U.S. Provisional Application Ser. No.61/080,150 filed Jul. 11, 2008, the entire contents of each of which areincorporated herein by reference in their entireties for all purposes.

TECHNICAL FIELD OF THE INVENTION

The present invention relates in general to the field of bone fixation,and more particularly, to a novel pedicle screw for use in thecorrection of mild to severe spinal deformities.

BACKGROUND OF THE INVENTION

Without limiting the scope of the invention, its background is describedin connection with pedicle screws.

In rigid severe spine deformity with coronal or sagittal decompensation,translation of the spinal column is necessary for restoration of trunkbalance as well as deformity correction. However, the conventionalcorrection methods, such as posterior correction only or anteriorrelease and posterior instrumentation, are usually unsatisfactory.Therefore, a more aggressive approach, such as reconstructivetechniques, is necessary. In 1922, Maclennan1 first illustratedvertebrectomy and demonstrated an apical resection from a posterior-onlyapproach with postoperative casting for the treatment of severescoliosis. Several authors2-8 have subsequently reported theirexperience with vetebrectomy, mostly for congenital scoliosis. In 1987,Bradford9 performed both anterior and posterior vertebral columnresection (VCR) with spinal shortening and posterior instrumentation andfusion demonstrating excellent restoration of coronal with relativelyfew complications. Leatherman6 introduced a two-stage anterior andposterior correction procedure for congenital spinal deformity. Bradfordand Bochie-Adjeil0 also reported a single stage anterior and posteriorresection of hemivertebra and spinal arthordesis. However, theanterior-posterior vertebral column resection (VCR) has disadvantagessuch as long operative time, potential significant blood loss, and riskof intraoperative neurologic impairment due to the spinal column segmentinstability during the resection and the correction procedure.

In 2002, Suk11-13 introduced a technique of a single posterior approachto perform VCR (PVCR) that offered significant advantages over thecombined anterior-posterior VCR. The surgery consisted of temporarystabilization of the vertebral column with segmental pedicle screwfixation, resection of the vertebral column at the apex of the deformityvia the posterior route followed by gradual deformity correction andglobal fusion. In the surgical technique, multiple pedicle screws wereutilized proximal and distal to the vertebral resection to securely fixthe spine prior to any bony resection. Provisional single rod placementis performed during the bony resection to prevent sudden spinal columntranslations which may result in spinal cord injury. The vertebralcolumn resection and deformity correction were carried out either byexchanging the temporary precontoured rods one by one or by in situ rodbending. However, these technique have a number of disadvantages: 1) therisk of intraoperative mishaps due to the instability resulting fromexchanging the temporary rods may produce spinal cord injury; 2)limitation in deformity correction secondary to a “one-time” correctionmaneuver utilized using the Suk technique; 3) short segment fixationusing the provisional rods since multiple exchanges prevent long rodutilization; and 4) additional surgical time necessary with multipleremoval and insertion of the temporary provisional rods.

One such fixation system is taught in U.S. Pat. No. 7,220,262, issued toHynes. Briefly, the spinal fixation system and related methods includepedicle screws secured in two columns, one along each side of the spine.Cross support rods have ends connected to pedicle screw heads. Alongitudinally extending rod is supported on the cross supports andrecessed in the cavity created by removal of portions of spinousprocesses, providing a reduced profile of the installed construct.Several types of cross supports are shown such as: arms from the screwsinward to rings or yokes connecting the longitudinal rod; cross rodswith ends connected to the screws and having centrally-located yokes forthe longitudinal rod; cross rods with articulating longitudinal rodportions fixed or swiveled to them. These cross rods may have endportions angled posterior toward anterior to accommodate lateralpositioned pedicle screws, but shorter cross rods without angled endportions enable medialized pedicle screw orientation.

U.S. Pat. No. 7,163,539, issued to Abdelgany, et al., is directed to abiased angle polyaxial pedicle screw assembly. Briefly, a pedicle screwassembly and method of assembly is taught that comprises a longitudinalmember; a screw head comprising a bulbous end, wherein the screw headhas a slot adapted to receive the longitudinal member; a bone fixatorcomponent comprising a concave socket having a biased angled top and arounded bottom adapted to receive the screw head; a locking pin adaptedto engage the screw head, the bone fixator component, and thelongitudinal member; and a blocker adapted to engage the screw head andto secure the longitudinal member. Additionally, the bone fixatorcomponent may be configured as any of a bone screw and a hook.

Yet another system is taught in U.S. Pat. No. 6,488,681, issued toMartin, et al., for a pedicle screw assembly. Briefly, a stabilizingassembly is taught that includes a fastener having an upper end and alower end, a head at the upper end, and at least one anchoring elementextending between the upper and lower ends. The head includes a center,an underside including a first radial surface and a top side including asecond radial surface. The first radial surface of the head defines afirst radius from the center of the head and the second radial surfacedefines a second radius from the center of the head, the first radiusbeing greater than the second radius. The assembly also includes acoupling element having an upper end and a lower end, the couplingelement including a rod receiving opening extending from the upper endthereof being adapted to receive a stabilizing rod, a bore extendingthrough the lower end of the coupling element for receiving thefastener, and a conical-shaped seat adjacent the lower end of thecoupling element adapted to engage the first radial surface of the headwhen the fastener is positioned in the bore. A locking elementassociated with the coupling element is adapted to apply a force upon astabilizing rod positioned in the rod receiving opening. As a force isapplied to a stabilizing rod, the rod in turn, engages the second radialsurface at the top side of the head for forcing the underside of thehead against the conical-shaped seat of the coupling element so as toprevent further pivotal and rotational movement of the fastener and thecoupling element relative to one another. In certain embodiments, thefastener may be a screw fastener having screw threads. In otherembodiments, the fastener may include a hook.

United States Patent Application No. 20070270810, filed by Sanders isdirected to a pedicle screw spinal rod connector arrangement. Briefly, apedicle screw spinal rod connector arrangement is provided that includesin a body having an opening for mounting a head of an inserted pediclescrew. A bracket connected with the body forms a lateral restraint. Abridge is connected with and extends over the body. A spinalrod-receiving slot is provided between the bridge and the bracket. Theconnector arrangement also has a wedge axially offset from the pediclescrew moveable downward by a setscrew mounted with the bridge. The wedgeimparts a locking force on the pedicle screw head and a generallylateral locking force on the spinal rod.

Yet another example is shown in United States Patent Application No.20070233062, filed by Berry for a pedicle screw system with offsetstabilizer rod. In this example, an improved pedicle screw system isprovided with an offset stabilizer rod for the internal fixation of thespine. The pedicle screw system includes at least two multi-anglepedicle screw units adapted for anchored securement to patient bone, andan elongated stabilizer rod extending therebetween. Each pedicle screwunit includes a bone screw associated with an anchor bracket defining alaterally offset and upwardly open channel or trough for receiving andsupporting the stabilizer rod. A securement member such as a set screwis fastened to the anchor bracket for compressively retaining thestabilizer rod within the bracket channel or trough. The securementmember may also bear against the associated bone screw for compressivelyretaining the screw in position relative to the anchor bracket.

SUMMARY OF THE INVENTION

The present invention solves various problems of current pedicle screwand spinal fixation systems. The present invention allows the surgeon tostabilize the spine, effectively derotate the spine, safely translatethe spine and when required easily derotate and translate the spine totreat spinal deformities.

The present inventors recognized there and other disadvantages of thecurrent implant strategies used during Posterior Vertebral ColumnResection (PVCR) by designing a new pedicle screw posteriorinstrumentation system. The present invention includes screws, methods,kits and systems that provide a safer, easier and better correction, aswell as shorter operation time method for the PVCR of the severe spinaldeformity. The present invention takes advantage of the top-loading andside-loading current designs as well as a universal connecting link toprovide three-dimensional correction. These components provide: 1)continued stabilization of the spine during bony resection as well ascorrection; 2) allow for controlled correction of the spine using bothrods; and 3) provide the ability to place the permanent rods while thelong provisional rod is in places so instability is not created.

The present invention includes: 1) a pedicle screw with a screw headthat can receive two rods. The bone screw head includes tworod-receivers. One receiver member is basic “U” shape (top-loadingcomponent) that extends from the top of the screw head to receive atemporary rod. Another receiver member has a basic “C” shape(side-loading component) that is inferior to the first receiver. Thesecond receiver receives a final rod. There is also a breakawaymechanism between the first and second apertures so that the firstaperture can be removed while the final rod is fixed; 2) rod-linkreducer has a basic “H” shape that rigidly links and locks the temporaryrods, which allows attachment to the rod at any orientation in thecoronal, sagittal, and transverse planes so as to make compression,distraction, derotation and cantilever method; 3) reduction handleconnects with the rod-link reducer; and 4) 5.5 mm diameter rod. For thePVCR of severe spinal deformity, this instrumentation system wouldprovide: 1) better maintenance of spinal stability throughout thesurgical procedure to reduce risk of the spinal cord injuries; 2) morereliable reconstruction of the vertebral column; 3) better and easiercorrection of the deformity; and 4) shorter operative time.

More particularly, the present invention includes a pedicle screw thatincludes: a bone fastener and a rod coupling head, the rod coupling headcomprising a lower and an upper rod coupling, wherein the lower rodcoupling has a lateral rod opening adapted to receive a permanent rod;an angled bore extends into the lateral rod opening; and a permanent rodfastener in the angled bore to engage a permanent rod in the lateral rodopening; and the upper rod coupling has an upper rod opening adapted toreceive a temporary rod, wherein the upper rod opening is formed toreceive a temporary rod fastener, wherein the upper rod coupling isdetachable from the lower rod coupling at a transition; wherein atemporary rod is temporarily affixed into the upper rod opening during abone realignment and a permanent rod is positioned in the lateral rodopening and engaged by the permanent rod fastener upon final bonealignment. In one aspect, the lower and upper rod couplings are integraland the transition between the first and second coupling assemblies isbreakable. In another aspect, the lower and upper rod couplings areintegral and a transition between the first and second couplingassemblies is semi-permanently attached.

The transition between the lower and upper rod couplings comprises auniversal joint, a pivot, a slot, a collar, a bearing, a dove-tail, aball-joint, a gimbal, a level, or a sleeve. The pedicle screw may alsoinclude lateral and upper rod openings that are generally perpendicularor parallel. In one aspect, the temporary fastener, the permanentfastener or both fasteners threadably engage the temporary rod, thepermanent rod or both rods. In another aspect, the temporary, thepermanent or both fasteners are locking pins. In one embodiment, thetransition between the lower rod coupling and the bone fastenercomprises a universal joint, a pivot, a slot, a collar, a bearing, adove-tail, a ball-joint, a gimbal, a level, or a sleeve.

In another embodiment, the present invention includes a method of spinalfixation using pedicle screws by fastening two or more pedicle screwinto two or more vertebra, the pedicle screw including a bone fastenerand a rod coupling head, the rod coupling head comprising separate lowerand upper lower rod couplings: the lower rod coupling including alateral rod opening adapted to receive a permanent rod; an angled boreextends into the lateral rod opening; and a permanent rod fastener inthe angled bore to engage a permanent rod in the lateral rod opening;and the upper rod coupling including an upper rod opening adapted toreceive a temporary rod, wherein the upper rod opening is formed toreceive a temporary rod fastener, wherein the upper rod coupling isdetachable from the lower rod coupling at a transition; interconnectingthe pedicle screws with a temporary rod. Next, the method includescorrecting the position of the spine by manipulating the temporary rodattached to the pedicle screws; interconnecting the pedicle screws witha permanent fixation rod; and removing the temporary rod and the upperrod coupling from the two or more pedicle screws.

In one aspect of the method of the present invention, the lower andupper rod couplings are integral and the transition between the firstand second coupling assemblies is breakable. In another aspect, thelower and upper rod couplings are integral and a transition between thefirst and second coupling assemblies is semi-permanently attached. Thetransition between the lower and upper rod couplings comprises auniversal joint, a pivot, a slot, a collar, a bearing, a dove-tail, aball-joint, a gimbal, a level, or a sleeve. The method of the presentinvention also includes using a rod link reducer to perform the step ofcorrecting the spine.

In another embodiment, the present invention includes a kit thatincludes two or more pedicle screw into two or more vertebra, thepedicle screw comprising a bone fastener and a rod coupling head, therod coupling head having separate lower and upper lower rod couplings:the lower rod coupling including a lateral rod opening adapted toreceive a permanent rod; an angled bore extends into the lateral rodopening; and a permanent rod fastener in the angled bore to engage apermanent rod in the lateral rod opening; and a upper rod couplingincluding: an upper rod opening adapted to receive a temporary rod,wherein the upper rod opening is formed to receive a temporary rodfastener; and two or more temporary rod fasteners. The kit may alsoinclude at least one of: a permanent rod and a temporary rod; one ormore rod link reducers; and one or more leverage handles.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the features and advantages of thepresent invention, reference is now made to the detailed description ofthe invention along with the accompanying figures and in which:

FIG. 1 shows one embodiment of the pedicle screw 10 of the presentinvention.

FIGS. 2A to 2C show a cross-sectional view of the pedicle screw 10 inoperation.

FIGS. 3A and 3B show an isometric view and a cross-sectional view,respectively, of the pedicle screw 10.

FIGS. 4A and 4B show an isometric view and a cross-sectional view,respectively, of the pedicle screw 10.

FIGS. 5A and 5B show an isometric view and a cross-sectional view,respectively, of the pedicle screw 10.

FIGS. 6A and 6B show an isometric view and a cross-sectional view,respectively, of the pedicle screw 10.

FIGS. 7A and 7B show an isometric view and a cross-sectional view,respectively, of the pedicle screw 10.

FIG. 8 shows a rod link reducer 10 for use with the present invention.

FIG. 9 is a cross-sectional side view of one embodiment of the rod linkreducer 10 present invention.

FIG. 10 is a side view of one embodiment of a rod manipulator.

FIGS. 11 to 13 show the first step in a spinal fixation process.

FIG. 14 shows the use of the rod link reducer and pedicle screw of thepresent invention.

FIG. 15 shows an overlay of the planning and tools for a surgicalprocedure to correct a severe spinal deformity.

FIGS. 16A to 16E shows the invention in use a procedure that includesdistraction, translation and apical derotation for correction of asingle severe spinal curve.

FIGS. 17A to 17E shows the invention in use a procedure for correctionof a double major severe spinal curve (Thoracic and Lumbar curve).

FIG. 18 is a detailed view of one embodiment of an apical derotationwithout linking the two pedicle screws.

FIG. 19 is an isometric view of a design of the rod-link reducer of thepresent invention.

FIG. 20 is an isometric view rod-link reducer of the present invention.

FIG. 21 is an isometric view of another design of the rod-link reducerof the present invention.

FIG. 22 shows a six-segment plastic spine model was instrumented to testthree constructs: (1) temporary rod/apical rod-link reducer (leftpanel); (2) provisional rod (center panel); and (3) final rod (rightpanel).

FIG. 23 is an illustration showing the present invention having longupper rod couplings to receive the rod and has a reduction function.

FIGS. 24-27 are illustrations showing that the bone fastener issemi-permanently attached and can receive the rod at any direction.

FIGS. 28-29 are pictures illustrating a perspective view of a presentinvention with a screw driver and a short fixation rod.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

While the making and using of various embodiments of the presentinvention are discussed in detail below, it should be appreciated thatthe present invention provides many applicable inventive concepts thatcan be embodied in a wide variety of specific contexts. The specificembodiments discussed herein are merely illustrative of specific ways tomake and use the invention and do not delimit the scope of theinvention.

To facilitate the understanding of this invention, a number of terms aredefined below. Terms defined herein have meanings as commonly understoodby a person of ordinary skill in the areas relevant to the presentinvention. Terms such as “a”, “an” and “the” are not intended to referto only a singular entity, but include the general class of which aspecific example may be used for illustration. The terminology herein isused to describe specific embodiments of the invention, but their usagedoes not delimit the invention, except as outlined in the claims.

The treatment of severe rigid spinal deformity is a demanding anddifficult surgical challenge. The PVCR has been considered to be aneffective alternative to the conventional anteriorposterior VCR insevere rigid spinal deformity. However, the current implant strategiesused during PVCR afford the limited correction, potential risk of spinalcord injuries, and long operative time. This new instrumentation systemmay offer: 1) better maintenance of spinal stability throughout thesurgical procedure to reduce risk of the spinal cord injuries; 2) morereliable reconstruction of the vertebral column; 3) better and easiercorrection of the deformity; and 4) shorter operative time.

Implant Components: The instrumentation system may include one or moreof the following components: a pedicle screw, a rod-link reducer,reduction handle, temporary long rod, and final rod. The pedicle screwincludes a threaded shank for insertion into the bone and a screw headhaving a first aperture and a second aperture. The first aperture has abasic “U” (tulip) shape (top-loading component) that extends from thetop of the screw head and is open on both sides of the screw head toreceive a first longitudinal member (a temporary rod) and a set offemale threads formed in the inner walls of the first aperture. A firstcompression member engages the set of female threads of the firstaperture and the face of the first compression member contacts the firstlongitudinal member. The second aperture has a basic “C” shape(side-loading component) that lines up superior to the threaded shankand inferior to the first aperture. The second aperture is open on bothsides of the head to receive a second longitudinal member (a final rod).The second aperture also includes a second set of female threads thataccommodate a second compression member that screwably engages thesecond set of female threads and the face of the second compressionmember contacts the second longitudinal member. There is a breakawaymechanism between the first and second apertures.

The rod-link reducer has a basic “H” shape that rigidly links and locksthe first longitudinal members (temporary rods). The rod-link reducerincludes: 1) two top-tightening locking mechanisms (break-off setscrews) those provide access ensure the adequate grip on the temporaryrods by the set screws; 2) an adjustable central mechanism byfunctioning in a multi-axial manner, allows attachment to the rod at anyorientation in the coronal, sagittal, and transverse planes. Themechanism allows to make compression, distraction, derotation andcantilever method; 3) two adjustable lateral mechanisms (break-off setscrews) allow the locking mechanisms adequately to attach the temporaryrods; 4) two squared ends those connect with two reduction handles.

The reduction handle is a column shape and has two portion ends. Thefirst end has a squared access that connects with the squared end of therod-link reducer. The second end is a solid column. The temporary rodand the final rod are the diameter of 5.5 mm rods those are made ofstainless steel or titanium.

In operation, the present invention may be used as follows: With thespine exposed posteriorly, the pedicle screws will be insertedsegmentally, except for the resected levels (apex). The spine is thendivided into cephalad and caudal portions by the resected levels. At thecephalad portion, two temporary rods will be fixed on the convex andconcave side via the first aperture of the pedicle screw respectively.Another two temporary rods will be similarly fixed at the caudalportion. The two temporary rods on the concave side will be connectedwith a rod-link reducer and locked to the shape of the deformity withoutany attempt at correction. Resection of the vertebral column will beperformed at the convex side of the apex. Following resection on theconvex side, another rod-link reducer will be connected and locked onthe two convex temporary rods. The resection of the remaining vertebrawill be performed on the concave side.

Deformity correction is performed by loosening the adjustable centralmechanism of the rod-link reducer on the convex side with the reductionhandles, which will be gradually compressed to shorten the resected gap.During the compression the resected gap on the convexity, the centralpart of rod-link reducer on the concavity will be gradually loosen tomatch the compression/shortening on the convexity.

After deformity correction, two final rods will be fixed on the convexand concave side via the second aperture of the pedicle screwrespectively. The two rod-link reducers will be unlocked and alltemporary rods will be removal. A custom wrench will be used to removethe first aperture parts of the pedicle screw.

The pedicle screw and any of its components including the bone fastener,threads, neck and screwhead, may be made of a non-organic material thatis durable and that can be implanted in a human body, such as titanium,stainless steel, spring steel, aluminum, Niobium, carbon fiber,ceramics, polymers, composites or any relatively hard material (e.g.Titanium-Aluminum-Niobium-alloy). Generally, the material selected willbe biocompatible, that is, compatible with the surrounding bone andtissue.

The present invention provides a substantial improvement in addressingclinical problems indicated for surgical treatment of chronic or acutespinal injuries, including traumatic spinal injuries, scoliosis(abnormal lateral curvature of the spine), kyphosis (abnormal forwardcurvature of the spine, often in the thoracic spine), excess lordosis(abnormal backward curvature of the spine, often in the lumbar spine),spondylolisthesis (forward displacement of one vertebra over another,often in a lumbar or cervical spine) and other disorders caused byabnormalities, disease or trauma, such as ruptured or slipped discs,degenerative disc disease, fractured vertebra, and the like.

FIG. 1 shows one embodiment of the pedicle screw 10 of the presentinvention. The pedicle screw 10 includes a bone fastener 12 and a rodcoupling head 14. The rod coupling head 14 includes a lower rod coupling16 having a lower rod opening 18, depicted in a lateral configuration.The lower rod opening 18 may have any angle so long as the material ofthe pedicle screw 10 that surrounds the lower rod opening 18 issufficiently strong to retain and affix a permanent rod. The lower rodcoupling 16 also includes a bore 20, through which a permanent rodfastener 22 can be inserted to fasten a permanent rod. As in the case ofthe lower rod opening 18, the material of the pedicle screw 10surrounding the bore 20 will also be sufficiently strong to retain andaffix a permanent rod. The upper rod coupling 24 has an upper rodopening 26. The upper rod coupling 24 is formed to permit the user toinsert a temporary rod using a temporary rod fastener 28. The lower andupper rod couplings 16 and 24, respectively, will often be made ofunitary construction. For illustration purposes, and not necessarily asan element or limitation, a transition 32 is denoted. In unitaryembodiments, the transition 32 may be modified (e.g., notched, cut,scratched or weakened) to provide for the breakage of the upper rodcoupling 24. In another embodiment, the transition 32 may provide asemi-permanent attachment between the lower rod coupling 16 and theupper rod coupling 24, such that the transition is a universal joint, apivot, a slot, a collar, a bearing, a dove-tail, a ball-joint, a gimbal,a level, or a sleeve. Likewise, the lower rod coupling 16 and the bonefastener 12 may be connected with a universal joint, a pivot, a slot, acollar, a bearing, a dove-tail, a ball-joint, a gimbal, a level, or asleeve. When made in a unitary construction, the pedicle screw 10 may bemachined, sintered, cast, welded or glued as long as the pedicle screw10 is of sufficient strength for the bone fixation application.

FIGS. 2A to 2C show a cross-sectional view of the pedicle screw 10 inoperation. In FIG. 2A, the pedicle screw has been affixed to a bone (notdepicted) and a temporary rod 34 has been inserted into the upper rodopening 26 and semi-permanently affixed using the temporary rod fastener28. In the embodiment depicted, the upper rod opening 26 is showsinternally threaded and the temporary rod fastener 28 is showsexternally threaded. The skilled artisan will recognize that the presentinvention also includes fastener embodiments in which the threading isreversed, the threading is external to the upper rod coupling and thefastener is internally threaded, the fastener is a cap, the fastener andthe coupling snap together, are wedged together, twist and lock.Likewise, the permanent rod fastener is also able to engage thepermanent rod in a variety of manners, including pins, latches,threading, snapping, wedging and locking. The permanent rod may even beglued or welded.

FIG. 2B shows the addition of the permanent rod 36 in addition to thetemporary rod 34. Next, the temporary rod fastener 28 and the temporaryrod are removed (not depicted). Finally, FIG. 2C shows the finalassembly in which the upper rod coupling is removed completely bybreaking the upper rod coupling into tabs 40 at breakpoints 38.

FIGS. 3A and 3B shows an isometric view and a cross-sectional view,respectively, of the pedicle screw 10 in which the lower rod coupling 16and the upper rod coupling 24 are connected by in which a screw portion50 is fastened into opening 52 and which permits the potential for somerotations about the axis of the screw portion 50. After the permanentrod has been affixed into the pedicle screw 10, the upper rod fastener24 is removed.

FIGS. 3A and 3B show an isometric view and a cross-sectional view,respectively, of the pedicle screw 10 in which the lower rod coupling 16and the upper rod coupling 24 are connected by in which a screw portion50 is fastened into opening 52 and which permits the potential for somerotations about the axis of the screw portion 50. After the permanentrod has been affixed into the pedicle screw 10, the upper rod fastener24 is removed.

FIGS. 4A and 4B show an isometric view and a cross-sectional view,respectively, of the pedicle screw 10 in which the lower rod coupling 16and the upper rod coupling 24 are connected by in which a screw 54 isfastened through opening 56 into opening 52 and which permits thepotential for some rotations about the axis of the screw 54. After thepermanent rod has been affixed into the pedicle screw 10, the upper rodfastener 24 is removed by unscrewing screw 54. The screw 54 also permitscontrol over the mechanical force required to rotate the upper rodcoupling 24. For configurations in which the lower rod coupling 16 andthe upper rod coupling 24 are separate, the interface between the twomake be smooth, rough or patterned (e.g., random or non-random) orcoated.

FIGS. 5A and 5B show an isometric view and a cross-sectional view,respectively, of the pedicle screw 10 in which the lower rod coupling 16and the upper rod coupling 24 are connected by in which a screw 54 isfastened through opening 56 into opening 52 and which permits thepotential for some rotations about the axis of the screw 54. After thepermanent rod has been affixed into the pedicle screw 10, the upper rodfastener 24 is removed by unscrewing screw 54. In this configuration thelower rod coupling 16 and the upper rod coupling 24 are separate and theinterface between the upper and lower rod couplings (24, 16) is enhancedby the addition of a slit 60 that dove-tails with a notch 62. The notch62 can even be placed at an angle or can also be made square such thatthe upper rod coupling 24 can be placed parallel or perpendicular to thedirection of the permanent or temporary rods.

FIGS. 6A and 6B show an isometric view and a cross-sectional view,respectively, of the pedicle screw 10 in which the lower rod coupling 16and the upper rod coupling 24 are connected by in which a screw 54 isfastened through opening 56 into opening 52 and which permits thepotential for some rotations about the axis of the screw 54. After thepermanent rod has been affixed into the pedicle screw 10, the upper rodfastener 24 is removed by unscrewing screw 54. In this configuration thelower rod coupling 16 and the upper rod coupling 24 are separate and theinterface between the upper and lower rod couplings (24, 16) is enhancedby the addition of a slit 60 that dove-tails with an external notch 62.The notch 62 can even be placed at an angle or can also be made squaresuch that the upper rod coupling 24 can be placed parallel orperpendicular to the direction of the permanent or temporary rods.

FIGS. 7A and 7B show an isometric view and a cross-sectional view,respectively, of the pedicle screw 10 in which the lower rod coupling 16and the upper rod coupling 24 are connected by in which a screw 54 isfastened through opening 56 into opening 52 and which permits thepotential for some rotations about the axis of the screw 54. After thepermanent rod has been affixed into the pedicle screw 10, the upper rodfastener 24 is removed by unscrewing screw 54. In this configuration thelower rod coupling 16 and the upper rod coupling 24 are separate and theinterface between the upper and lower rod couplings (24, 16) is enhancedby the addition of dove-tail joints (shown in two differentconfigurations). The notch 62 can even be placed at an angle or can alsobe made square such that the upper rod coupling 24 can be placedparallel or perpendicular to the direction of the permanent or temporaryrods.

FIG. 8 is an isometric view of a rod link reducer 100 for use with thepresent invention. The rod link reducer 100 includes first and secondspinal rod manipulators 102, 104, which are connected to a first spinalrod manipulator joint 106 connected to the first spinal rod manipulator102 and a second spinal rod manipulator joint 108 connected to thesecond spinal rod manipulator 104. First and second translatabletransverse shafts 110, 112 connected to the first and second joints 106,108, respectively, which connected to a reducer 114 connected to boththe first and second translatable transverse shafts 110, 112, whereinthe reducer 114, the shafts 110, 112 and the linkers 106, 108 providemovement and temporary fixation of a spine that has been manipulatedinto a final position during spinal surgery.

FIG. 9 is a cross-sectional side view of one embodiment of the rod linkreducer 10 present invention, shown in this embodiment with screws 116.The skilled artisan will recognize that the screws 16 provide reversiblemechanical fixation between the different parts of the system that canbe tightened and loosened during spinal adjustments. Any given joint mayinclude some friction or resistance during use up to and including totalfixation. The screws 116 can be replaced or include pins, set screws,cotter pins, internal or external compression, compression fittings,collared fittings, screw-drives or even electrical, pneumatic orhydraulic movement or pressure. In the embodiment depicted, first andsecond translatable transverse shafts 110, 112 as shown as adjustmentsleeves slidably fitted within a housing 118 is an axial bore 120 andwithin the axial bore a strut 122 in which the screw 116 serves as afastener positioned to secure the strut 122 within the housing 118,wherein the struts 112 allow for coarse longitudinal movement of thestrut 122 with respect to the strut housing 118. The skilled artisanwill recognize that the strut-bore configuration can be reversed(bore-strut) or replaced with side-by-side struts, internal-externalslidable pins within a groove, screw-drives, magnetic drives,electrical, pneumatic or hydraulic drives so long as the translatabletransverse shafts 110, 112 permit the user to expand and/or contract oneor both the translatable transverse shafts 110, 112.

FIG. 10 is a side view of one embodiment of rod manipulators 102, 104.In this side view screws 116 are shown as well as either first or secondjoint 106, 108. The rod manipulators 102, 104 include a head 130 thathas an opening 132 that first a rod (temporary or permanent) for spinalfixation. The screw 116 is used to engage and retain the rod. The rodmanipulators 102, 104 will be made from a material with sufficienttensile strength to allow the manipulator to fasten to the rod but alsoto permit the user to translate movement from the handle 134 into therod in any direction. The handle 134 may itself also include a coating(not depicted) to improve the grip of a user during use or may be shapedto permit a second handle to attach to the handle 134 to increase theleverage of a user when manipulating a spine during spinal fixationsurgery. Again, while this embodiment is shown with screws, anyfastening method (pins, set-screws, compression, collets, etc.) may beused to fasten the various components of the rod link reducer of thepresent invention.

The rod link reducer 100 may be used in conjunction with existing spinalscrew and rod fixation systems or may be used in conjunction with thepedicle screw 10. The size and thickness of rods may be varied dependingon the type of surgery, tensile strength required and preference of theuser.

FIG. 11 shows the first step in a spinal fixation process. In thisembodiment, a temporary rod 34 has been attached to pedicle screws 10(while not depicted, the pedicle screws may be attached individualvertebra. Examples of conditions that may be treated using the presentinvention include kyphosis, lordosis, scoliosis or combinations thereof.A rod link reducer 100 is shown connected to the temporary rod 34 andthe spine (not shown) has been aligned. In FIG. 12, the permanent rod 36is introduced into the pedicle screw 10 while the rod link reducer 110holds the entire assembly in place while the permanent rod ispermanently affixed to the pedicle screws 10. Finally, FIG. 13 shows thefinal spinal rod assembly after removing the permanent rod and thebreakable tabs from the pedicle screws 10.

FIG. 14 shows the advantage provided by the rod link reducer 100 of thepresent invention. In this top view of the operation of the presentinvention, two rod link reducers 100 a, 100 b are connected to two pairsof temporary rods 34 a-d and pedicle screws 10 a-h. By compressing,distracting or rotating the rod link reducers 100 a, 100 b, the user canmanipulate the spine in all directions necessary for spinal alignmentand fixation. Furthermore, the user is able to compress, distract, andtranslate any of the spinal segments until arriving at a final position.The rod link reducer 100 is tightened upon final positioning and thepermanent rod can be inserted into the pedicle screws. Furthermore, therod link reducers 100 a, 100 b can be tightened in a single plane at atime while still manipulating the rest of the spine in the other planes.

The present invention can be used to correct mild to severe spinaldeformities, including sever deformities. The present invention includesthe following advantages: a reduced risk of intraoperative mishaps dueto the instability caused by exchanging the temporary rods with thepermanent rod, it increases the directions in which the deformities canbe corrected and reduces the number of tools, and surgical time causedby temporary rod failure or slipping that occurs between the finalpositioning of the temporary rods and the fixation of the permanent rod.It has been found that the present invention allows the surgeon toshorten the duration of the operation and also increases the extent ofcorrection in a single procedure.

FIG. 15 shows an overlay of the planning and tools for a surgicalprocedure to correct a severe spinal deformity. An x-ray is shown of amalformed spine and the tools are overlaid to plan the positioning ofthe pedicle screws, rods and rod link reducer. Next, the user determinesthe various different steps in the correction, including thecompression, distraction, apical derotation and translation of one orboth pairs of temporary rods. Also shown are optional tools or handlesto increase the leverage of the surgeon, taking into account theaccessibility of tools due to the translation and rotation of theunderlying spine prior to treatment. In certain cases, the steps may bealternated to maximize the leverage of the rod link reducers indifferent direction, thereby maximizing efficiency of the movement,increasing the effectiveness of the procedure and minimizing the time ofthe procedure.

FIGS. 16A to 16E shows the invention in use a procedure that includesdistraction, translation and apical derotation. FIG. 16A shows a singleright thoracic rigid curve 200. FIG. 16B shows the first step in theprocedure in which temporary rods 34 a and 34 b, which are fixed at aproximal portion of the spine and another one fixed at distal portion ofthe curve about a concavity. The temporary rods 34 a, 34 b are attachedto the single right thoracic rigid curve 200 using pedicle screws (notdepicted) on either end of the site for distraction, translation andapical derotation. One example of the pedicle screws that may be used inthe procedure is pedicle screw 10. FIG. 16C shows the rod link reducer100 connected to temporary rods 34 a and 34 b on the concavity. Next,derotation instruments 202 a-c are attached to the apical vertebrae.FIG. 16D shows the combined distraction, translation and apicalderotation of the spine in which the rod link reducer 100 is used forthe distraction and translation (arrows) and the derotation instruments202 a-c, seen as a cross-sectional view of the spine at a vertebrae 304,is are used alone or in combination (in this instance) for apicalderotation via linker 308 attached to pedicle screws 310. The skilledartisan will recognize that these tools may be used for a distraction,translation and/or apical rotation, however, most procedures willinvolve a combinations of these manipulations. FIG. 16E shows avariation of the combined distraction, translation and apical derotationoutlined in FIGS. 16A-16D in which pairs of temporary rods 34 a, 34 bare shown in parallel along the proximal and distal segments of thespine. A second rod link reducer 101 is shown as two provisional rods 34are on the concavity. Convex provisional compression is to help thecurve correction.

FIGS. 17A to 17E shows the use of the rod link reducer 100 on a spinalconvexity.

FIG. 17A shows a right thoracic rigid curve 300 onto which two temporaryrods 34 a, 34 b are on the concavity of the thoracic curve and twotemporary rods 34 c, 34 d are on the concavity of the lumbar curve asshown in FIG. 17B. FIG. 17C shows the attachment of two rod-linkreducers 100 a, 100 b fixed on the concavity for both curves,respectively. Next, the combined distraction, translation and apicalderotation for both curves is depicted in which derotation instruments202 a-c and 202 d-e are attached to the vertebrae 204, 305 throughpedicle screws 306 via linkers 308. The linkers 308 serve as attachmentpoints for the derotation instruments 202 a-e and can be used toincrease the leverage for the distraction, translation and apicalderotation. FIG. 17E shows the positioning of a pair of convex temporaryrods at each site are used for compression maneuvers to help in thecorrection of the two curves using two rod link reducers 100, 101 abouteach of the treatment sites.

FIG. 18 is a detailed view of one embodiment of an apical derotationwithout linking the two pedicle screws 310 a, b. In this embodiment, thelinkers 308 a, b are used directly to aid in the apical rotation of asingle vertebrae 304 without a linked derotation instrument.

FIGS. 19, 20 and 21 shows various designs of the rod-link reducer 100.FIG. 19 shows a rod link reducer 100 that includes a universal connecteron the central portion. The rod link reducer 100 includes first andsecond spinal rod manipulators 102, 104, which are connected to a firstspinal rod manipulator joint 106 connected to the first spinal rodmanipulator 102 and a second spinal rod manipulator joint 108 connectedto the second spinal rod manipulator 104. First and second translatabletransverse shafts 110, 112 slides through joints 106, 108, respectively.The joints 106, 108 can tighten to fix the transverse shafts 110, 112individually. In FIG. 19, the two translatable transverse shafts 110,112 have movement around a reducer 114, which is depicted as a singlereducer with universal movement. In one example, the reducer 114 may befixed to act as a straight rod to limit the movement of the first andsecond spinal rod manipulators 102, 104 in two planes. FIGS. 20 and 21show the rotation between the rod-connecter. This design would bestronger and easily to install and give surgeons more free for surgery.

As the skilled artisan will appreciate the first and second translatabletransverse shafts 110, 112 may be in-line, as depicted in FIGS. 19-21,or may be parallel on two separate planes allowing the first and secondtranslatable transverse shafts to extend past the ends of the oppositeshaft. By allowing the first and second translatable transverse shaftsto move in parallel, the distance between first and second spinal rodmanipulators 102, 104 can be reduced to a minimum in certainmanipulations. As can also be seen from these figures, the first andsecond rod manipulator joints 106, 108 can slide toward or away from thetemporary rods 34 a,b. The configuration presented herein allows sixdegrees of freedom in any direction, while also providing the necessarystrength and leverage to perform complex spinal deformity surgery in areduced space.

FIG. 23 shows the present invention with extended upper rod coupling 24that can be reduced or removed if necessary. FIG. 24 shows that the bonefastener 12 is semi-permanently attached to the lower rod coupling 16.FIGS. 24 to 27 show that the bone fastener 12 can be orientated atdifferent angles relative to the rod coupling 16. The angle can varyfrom any direction and can contain different degrees. For example, thetip of the bone fastener can resemble a circular ball bearing thatallows the bone screw to be position in any direction of the x y zplane. FIGS. 28 and 29 show different perspective views of the presentinvention with a screw driver 118 and a short fixation rod 120. When theshort fixation rod 120 is tightened by the rod fastener 22, the pediclescrew 10 is not polyaxial so that the pedicle screw 10 can be insertedby the screw-driver 118. When the rod fastener 22 is loosened, thepedicle screw 10 can polyaxially receive the rod at any direction.

The present invention overcomes the following disadvantages of existingsystems, namely, the limitation for the apical vertebral derotation andtranslation. Another disadvantage or existing systems is the difficultyfor concave rod derotation and/or translation which result in pediclescrew loosening with damage to the spinal cord. The present inventionovercomes both of these advantages by providing a stable, sturdyplatform for use of temporary and permanent rods using a single pediclescrew. The pedicle screw of the present invention maximizes thestructural-mechanical properties of each fixation point (the lowerversus the upper rod coupling) for each specific type of rod (permanentor temporary) while at the same time maximizing the efficiency of thesurgical procedure with less tools and equipment. Furthermore, surgeonsare already familiar with similar tools and fasteners and do not have tolearn new procedures, techniques or the use of new tools.

It is contemplated that any embodiment discussed in this specificationcan be implemented with respect to any method, kit, reagent, orcomposition of the invention, and vice versa. Furthermore, compositionsof the invention can be used to achieve methods of the invention.

It will be understood that particular embodiments described herein areshown by way of illustration and not as limitations of the invention.The principal features of this invention can be employed in variousembodiments without departing from the scope of the invention. Thoseskilled in the art will recognize, or be able to ascertain using no morethan routine experimentation, numerous equivalents to the specificprocedures described herein. Such equivalents are considered to bewithin the scope of this invention and are covered by the claims.

All publications and patent applications mentioned in the specificationare indicative of the level of skill of those skilled in the art towhich this invention pertains. All publications and patent applicationsare herein incorporated by reference to the same extent as if eachindividual publication or patent application was specifically andindividually indicated to be incorporated by reference.

The use of the word “a” or “an” when used in conjunction with the term“comprising” in the claims and/or the specification may mean “one,” butit is also consistent with the meaning of “one or more,” “at least one,”and “one or more than one.” The use of the term “or” in the claims isused to mean “and/or” unless explicitly indicated to refer toalternatives only or the alternatives are mutually exclusive, althoughthe disclosure supports a definition that refers to only alternativesand “and/or.” Throughout this application, the term “about” is used toindicate that a value includes the inherent variation of error for thedevice, the method being employed to determine the value, or thevariation that exists among the study subjects.

As used in this specification and claim(s), the words “comprising” (andany form of comprising, such as “comprise” and “comprises”), “having”(and any form of having, such as “have” and “has”), “including” (and anyform of including, such as “includes” and “include”) or “containing”(and any form of containing, such as “contains” and “contain”) areinclusive or open-ended and do not exclude additional, unrecitedelements or method steps

The term “or combinations thereof” as used herein refers to allpermutations and combinations of the listed items preceding the term.For example, “A, B, C, or combinations thereof” is intended to includeat least one of: A, B, C, AB, AC, BC, or ABC, and if order is importantin a particular context, also BA, CA, CB, CBA, BCA, ACB, BAC, or CAB

Continuing with this example, expressly included are combinations thatcontain repeats of one or more item or term, such as BB, AAA, AB, BBC,AAABCCCC, CBBAAA, CABABB, and so forth. The skilled artisan willunderstand that typically there is no limit on the number of items orterms in any combination, unless otherwise apparent from the context.

All of the compositions and/or methods disclosed and claimed herein canbe made and executed without undue experimentation in light of thepresent disclosure. While the compositions and methods of this inventionhave been described in terms of preferred embodiments, it will beapparent to those of skill in the art that variations may be applied tothe compositions and/or methods and in the steps or in the sequence ofsteps of the method described herein without departing from the concept,spirit and scope of the invention. All such similar substitutes andmodifications apparent to those skilled in the art are deemed to bewithin the spirit, scope and concept of the invention as defined by theappended claims.

REFERENCES

-   1. Maclennan A. Scoliosis. Br Med J 1922; 2: 865-6.-   2. Compere E L. Excision of hemivertebrae for correction of    congenital scoliois: report of two cases. JBJS 1932; 14-A; 555-62.-   3. Deviten V, Berven S, Smith J A, et al., Excision of hemivertebrae    in the management of congenital scoliosis involving the thoracic and    thoracolumbar spine. JBJS 2001; 83-B; 496-500.-   4. Floman Y, Penny J N, Micheli L J, et al. Osteotomy of the fusion    mass in scoliosis. JBJS 1982; 64-A: 1307-16.-   5. Luque E R. Vertebral column transposition. Orthop Trans 1983; 7:    29.-   6. Leatherman k D, Dickson R A. Two-stage corrective surgery for    congenital deformities of the spine. JBJS 1979; 61-B: 324-8.-   7. Tokunaga M, Minami S, Kitahara H, et al. Verteral decancellation    for severe scoliosis. Spine 2000; 25: 469-74-   8. Wiles P. Resection of dorsalvertebrae in congenital scoliosis.    JBJS 1951, 33-A: 151-4.-   9. Bradford D S. Vertebral column resection. Orthop Tans 1987; 11:    502.-   10. Bradford D S and Boachie-Adjei O. One-stage anterior and    posterior hemivertebral resection and arthrodesis for congenital    scoliosis. JBJS 1990; 72-A: 536-40.-   11. Suk S, Kim J H, Kim W J, et al. Posterior vertebral column    resection for severe spinal deformities. Spine 2002; 27 (21):    2374-82.-   12. Suk S, Chung E R, Kim J H, et al. Posterior vertebral column    resection for severe spinal deformities. Spine 2005; 30 (14):    1682-87.-   13. Suk S, Chung E R, Lee S M, et al. Posterior vertebral column    resection in fixed lumbosacral deformity. Spine 2005; 30 (23):    E703-10.

What is claimed is:
 1. A method of bone fixation comprising: attaching apedicle screw to a bone, the pedicle screw comprising a rod couplinghead having a lower rod opening and an upper rod opening; inserting afirst rod into the lower rod opening; inserting a second rod into theupper rod opening, wherein the upper rod opening is formed between apair of tabs each of which have breakpoints; securing the first rod intothe lower rod opening with a first fastener; securing the second rodinto the upper rod opening with a second fastener, wherein the first andsecond fasteners are at different angles relative to one another;removing the second rod, and breaking off the pair of tabs at thebreakpoints.
 2. The method of claim 1, wherein the first rod isside-loaded into the lower rod opening.
 3. The method of claim 1,wherein the second rod is top-loaded into the upper rod opening.
 4. Themethod of claim 1, wherein the first rod is a permanent rod.
 5. Themethod of claim 1, wherein the second rod is a temporary rod.
 6. Themethod of claim 1, wherein the first fastener is at an angle relative toa vertical axis through the pedicle screw.
 7. The method of claim 1,wherein the second fastener is inline relative to a vertical axisthrough the pedicle screw.
 8. The method of claim 1, further comprisinga second pedicle screw.
 9. The method of claim 8, further comprisingpositioning a rod link reducer between the pedicle screw and the secondpedicle screw.
 10. The method of claim 9, wherein the rod link reducercomprises a first rod manipulator and a second rod manipulator.
 11. Themethod of claim 10, further comprising connecting the first rodmanipulator to a first spinal rod manipulator joint and connecting thesecond rod manipulator to a second rod manipulator joint.
 12. The methodof claim 11, further comprising connecting the first spinal rodmanipulator joint and the second rod manipulator joint to the rod linkreducer.
 13. The method of claim 9, wherein the rod link reducer isH-shaped.
 14. A method of bone fixation along a spine comprising:attaching a pedicle screw to a bone, the pedicle screw comprising a rodcoupling head having a lower rod coupling portion defining a firstopening and an upper rod coupling portion defining a second opening;inserting a permanent rod into the first opening; inserting a temporaryrod into the second opening; securing the permanent rod into the firstopening with a first fastener; securing the temporary rod into thesecond opening with a second fastener, wherein the first and secondfasteners are at different angles relative to one another; correcting adeformity along the spine; removing the temporary rod; and removing theupper rod coupling portion.
 15. The method of claim 14, wherein thepermanent rod is side-loaded into the first opening.
 16. The method ofclaim 14, wherein the temporary rod is top-loaded into the secondopening.
 17. The method of claim 14, wherein the upper rod couplingportion is defined by a pair of tabs.
 18. The method of claim 17,wherein removing the upper rod coupling portion includes breaking offthe pair of tabs at breakpoints.